Exercise reduces arterial pressure augmentation through vasodilation of muscular arteries in humans

Abstract

Exercise markedly influences pulse wave morphology, but the mechanism is unknown. We investigated whether effects of exercise on the arterial pulse result from alterations in stroke volume or pulse wave velocity (PWV)/large artery stiffness or reduction of pressure wave reflection. Healthy subjects (n = 25) performed bicycle ergometry. with workload increasing from 25 to 150 W for 12 min. Digital arterial pressure waveforms were recorded using a servo-controlled finger cuff. Radial arterial pressure waveforms and carotid-femoral PWV were determined by applanation tonometry. Stroke volume was measured by echocardiography, and brachial and femoral artery blood flows and diameters were measured by ultrasound. Digital waveforms were recorded continuously. Other measurements were made before and after exercise. Exercise markedly reduced late systolic and diastolic augmentation of the peripheral pressure pulse. At 15 min into recovery, stroke volume and PWV were similar to baseline values, but changes in pulse wave morphology persisted. Late systolic augmentation index (radial pulse) was reduced from 54 +/- 3.9% at baseline to 42 +/- 3.7% (P < 0.01), and diastolic augmentation index (radial pulse) was reduced from 37 +/- 1.8% to 25 +/- 2.9% (P < 0.001). These changes were accompanied by an increase in femoral blood flow (from 409 +/- 44 to 773 +/- 48 ml/min, P < 0.05) and an increase in femoral artery diameter (from 8.2 +/- 0.4 to 8.6 +/- 0.4 mm, P < 0.05). In conclusion, exercise dilates muscular arteries and reduces arterial pressure augmentation, an effect that will enhance ventricular-vascular coupling and reduce load on the left ventricle.

Impact of passive vibration on pressure pulse wave characteristics

“…However, AIx and P2 changes after acute exercise and vasoactive drug infusion are due to vasodilation of muscular arteries. 9,35 An additional limitation of the present study is that our measurements were limited to 32 min after the end of the PV, and hence we cannot determine the precise duration of the decrease in AIx. However, it appears that the peak reduction in AIx (B5%), which occurs 15-30 min after the end of an acute bout of cycling, is no longer apparent at 60 min after the exercise.…”

“…[9][10][11] Similarly, 10 sets of static squat exercise with addition of WBV (10 min intermittent exposure to vibration) decreases AIx (B4%). 17 The post-exercise AIx reduction has been attributed to arteriolar and muscular artery vasodilation in the exercised limbs.…”

“…17 The post-exercise AIx reduction has been attributed to arteriolar and muscular artery vasodilation in the exercised limbs. 9,10 Indeed, repeated muscle contractions ASBP (mm Hg) CON 94 ± 7 9 4 ± 6 9 4 ± 7 PV 95±7 9 5 ±8 9 4 ±7 ADBP (mm Hg) CON 65 ± 7 6 3 ± 7 6 6 ± 6 PV 64 ± 5 6 5 ± 6 6 6 ± 6…”

“…33 In addition, it appears that PV increases local blood flow by increasing endothelial nitric oxide production, 20 while reducing the circulating levels of the vasoconstrictor endothelin-1. 34 Similarly, vasodilation of peripheral arteries by exercise 9 and vasoactive drugs 35 can significantly influence wave reflection by decreasing the tone of small muscular arteries. Reduction of the amplitude of the reflected wave causes a decrease in AP and AIx, leading to a reduction in left ventricular afterload.…”

“…However, it appears that the peak reduction in AIx (B5%), which occurs 15-30 min after the end of an acute bout of cycling, is no longer apparent at 60 min after the exercise. 9 In addition, Otsuki et al 13 noted that brachial-to-ankle pulse wave velocity, which includes leg arterial stiffness, remained reduced 40 min after 10 min of intermittent static exercise with WBV. Therefore, based on the magnitude of the AIx response after PV (À7.1%), we speculate that this effect may persist between 40 and 60 min after the end of the PV session.…”